Cochlear implants: Three-dimensional localization by means of coregistration of CT and conventional radiographs

With use of radiopaque implanted objects as internal fiducial markers, the authors developed and evaluated a technique for coregistering computed tomo graphic (CT) and computed radiographic images to help determine three-dimen sional location information for implant electrodes in the cochlea in phanto ms and patients. Three-dimensional positional data from CT were assigned on a radiograph, which permitted identification of individual cochlear electr ode locations that were not depicted at CT.